1. Field of the Invention:
This invention relates to a multi-computer system in which a plurality of computers are employed for controlling an industrial process and more particularly to a multi-computer system in which one computer acts as a schedule master for the others.
2. Description of the Prior Art
In the art of industrial process control, it is well known to increase the level of digital control by using a multi-computer system which includes a plurality of electronic computers. Such multi-computer systems for industrial process control have attracted special interest recently because of the improving cost performance of mini-computers and micro-computers.
In accordance with prior multi-computer systems, the system generally includes a plurality of computers for controlling or inspecting respectively different parts of the industrial process and a bulk memory device commonly accessible through a multi-access controller. Consequently when the system is busy, such as when numerous invocations or requests for creating the activity internal to the computer occur from the industrial process, the multi-access controller is overloaded by many invocations so that many of the latter have to be stored temporarily before internal activities can begin.
This may undesirably cause reduced responsiveness in the industrial process control to which the multi-computer system is applied. If the resulting response time of the control computer is lengthened beyond required limits, appliances in the industrial process which are controlled by the control computer cannot receive appropriate control signals at an appropriate time so that the appliances will not operate properly, producing products having defects and possibly causing faults in the appliances themselves.